History on Ice

bout 45,000 years ago, in the midst of the last ice age, modern humans began arriving in what we now call Europe. They stayed even as temperatures fell and great glaciers crept to their maximum coverage between 25,000 and 19,000 years ago.

Archaeologists have unearthed traces of these hunter-gatherer cultures in bones, tools, cave paintings and other artifacts. That record, however, can only hint at how members of different populations were related to one another and to present-day people.

By analyzing genome-wide data from the remains of 51 humans who lived between 45,000 and 7,000 years ago, an international research team has provided the first vivid look at the genetic history of modern humans in Europe before the introduction of farming.

he team’s findings, published May 2 in Nature, reveal the disappearance and reappearance of a group that formed part of the ancestry of today’s Europeans, describe when and how Europeans acquired DNA from people in the Near East and show that the amount of Neanderthal DNA in modern human genomes has shrunk over the millennia, likely because the DNA was evolutionarily disadvantageous.

“This study raises by about tenfold the number of ice age hunter-gatherers for which there is ancient DNA, and in so doing, it makes it possible to track genetic change over time,” said David Reich, professor of genetics at Harvard Medical School and co-senior author of the paper.

“Prior to this work, we had a static view of the first 30,000 years of modern human history in Europe. Now we can begin to see how people moved around and mixed with one another during this period,” said co-senior author Svante Pääbo, director at the Max Planck Institute for Evolutionary Anthropology in Leipzig, Germany.

“Archaeologists have gathered a tremendous amount of information about cultural change in ice age Europe,” said co-senior author Johannes Krause, professor of archaeo- and paleogenetics at the University of Tübingen and director at the Max Planck Institute for the Science of Human History in Jena, Germany. “This study connects our knowledge of the material culture of ice age populations—including people who produced elaborate figurines and the world’s first musical instruments—to their biological identities.”